first step forward to starting a career in software testing

dear friends
i am intrested in starting a career in software testing.please guide me in step by step approach to start a career in this field.i need to know the basic of testing software and how to begin as a new user?please guide me.
thanks

Rumana,
I highly recommend this book to understand at a high level how all the pieces fit together.

For a lower level, check the job listings in your area for entry level software testing positions. What do they want? Then see if you can learn one of the tools. Also read about lower level testing concepts like how to come up with test cases - what is black box vs white box testing. And ask people who are currently employed as testers.